Handheld Probes and Mini-Cameras

for Intraoperative Guidance during

Surgery

Peter Knoll

Dept. of Nuclear Medicine with PET Center

Vienna, AUSTRIA

NAME : Dr. Peter Knoll

AFFILIATION: Wilhelminenspital

In accordance with criterion 24 of document UEMS 2012/30 “Accreditation of Live

Educational Events by the EACCME”, all declarations of potential or actual conflicts of

Conflict of Interest Disclosure Form

Educational Events by the EACCME”, all declarations of potential or actual conflicts of

interest, whether due to a financial or other relationship, must be provided to the

EACCME® upon submission of the application. Declarations also must be made readily

available, either in printed form, with the programme of the LEE, or on the website of the

organiser of the LEE. Declarations must include whether any fee, honorarium or

arrangement for re-imbursement of expenses in relation to the LEE has been provided.

DISCLOSURE

I have no potential conflict of interest to report

Intraoperative Gamma probes

– Clinical Applications*

Breast, gastrointestinal, head-neck, gynecoligic, ureologic, thoracic, , NET, …

– IsotopesTc99m, Iodine 125, 131

Indium 111, Fluorine 18

Gallium 68

– Radiation detectorsScintillation detectors, Semiconductor Ionization detectors

– PerformanceRadial Sensitivity distribution

Spatial resolution

Energy resolution

Shielding and Collimation

Display

*Povoski SP et al: A comprehensive overview of radioguided surgery using gamma detection probe technology.

World J Surg Oncol 2009 Jan 27;7:11. doi: 10.1186/1477-7819-7-11

http://www.neoprobe.com

www.carewise.comwww.crystal-gmbh.com

Gamma Probe, RMD Instruments

http://www.medecine-nucleaire.lu

http://www.gammaprobe.com/products/gamma-probes/

www.gammafinder.com

Radioguided Sentinel Lymph Node

(SLN) Surgery

Basic idea:

The tumor drains in a logical way through the lymphaticsystem.

The first node encountered (sentinel node) will mostlikely be the first affected by metastasis.likely be the first affected by metastasis.

Involved departments

Nuclear medicine

Surgery, gynaecology

Setup Detector unit-Scintillator

-Si-Diode

Electronics Battery

Collimator Body Bluetooth

Scintillation detectors: NaI(Tl), CsI(Tl), CsI(Na), BGO, LSO

Semiconductor Ionization detectors: CdTe, CZT, HgI2

Basic design of an intraoperative probe

The collimator is characterized by its

aperature, length and wall thickness.

The probes FOV increases with increasing

distance from the detector aperature

Heller S. and Zanzonico P.: Nuclear probes and intraoperative gamma cameras.

Seminars in Nuclear Medicne2011 May;41(3):166-81.

The collimation influences the sensitiviy and spatial resolution.Material: to maximize attenuation high-atomic number materials should be

used: Lead, tungsten, gold, platinium

Gamma Probes: Collimator

Heller S.,

Energy resolution: Comparison

20000

25000

3000

3500

4000

CZT Scintillationdetector

Co-57 Co-57

Full-Width at Half-Maximum (FWHM) expressed as the percentage of the photopeak

energy

0

5000

10000

15000

20 40 60 80 100 120 140 160 180

Co

un

ts

Energy [keV]

FWHM: 6.46 keV

ER: 5.3 %

0

500

1000

1500

2000

2500

3000

20 40 60 80 100 120 140 160 180

Co

un

ts

Energy [keV]

FWHM: 34 keV

ER: 27 %

Sensitivity• Max. radionuclide uptake: 0.01-1 %

• Applying 99mTc-Nanocolloid: 0.05% to 0.005% uptake in lymphnode isfound intraoperativly

• Activity: 80MBq

• Sensitivity measurement for SLN ≥ 5cps/kBq

• Measurement procedure:

Directly on the tip of the probe or collimator

• Typical values (Wengenmair, H. et al. Nuklearmediziner; v. 22(4); Oct 1999; p. 271-280)

• : 23-0.3 cps/MBq

Detector Performance:

Radial sensitivity distribution

The sensitivity distribution is evaluated equidistant to the frontal radiation entrance

window dependant on the polar angle.

The full width at half maximum (FWHM) of the distribution function is a good

quality criterion for the detectability of lymph nodes in presence of non target

radiation (injection depot, background).

With a broad measurement cone the background signal can exceed the target With a broad measurement cone the background signal can exceed the target

signal of the lymph node, which then cannot be detected.

A small cone mainly reduces background maintaining a constant target signal.

Therefore with increased background in the target area a smaller FWHM of radial

sensitivity distribution is desired.

Radial sensitivity distributionBroad radial sensitiviy distribution

Inhomogeneous background

within the measurement field

Target

Signal[cps]

Back-ground

Target

=>Target not detectable

within the measurement field

Small radial sensitiviy distribution Signal[cps]

Back-ground

Target

=>Target detectable

Typ. Values (Wengenmair, H. et al. Nuklearmediziner; v. 22(4); Oct 1999; p. 271-280)

60° collimator: 23°, 30° collimator: 13°, 15° collimator: 10°

Detector performance: Spatial resolution

Measurement procedure:Probe is scanned laterally above a 9mmTc point source.

The FWHM gives the minimal distances at which two pint sources can be

detected separately.

Typical values:

24 mm - 8 mm

FWHM=15mm

Point sources

25mm

distance

0

0,2

0,4

0,6

0,8

1

0 15 30 45 60 75

lateral

scanning

rel. signal

lat.

Abs

tand

[m

m]

0

0,2

0,4

0,6

0,8

1

0 15 30 45 60 75

FWHM=28mm

rel. signal

Typ. FWHM values (Wengenmair, H. et al. Nuklearmediziner; v. 22(4); Oct 1999; p. 271-280)

60° collimator: 12 mm, 30° collimator: 8 mm, 15° collimator: 5mm

Shielding

Target (SLN)

Apparent SLN in the measurement cone by background

activity nearby a shielding leak.

Shielding leak

hot disturbing activity outside the measurement cone(z.B. Injektionsdepot)

measurement cone

Typ. values: 0.1-8.2%

Wengenmair, H. et al. Qualitätskriterien und Vergleich von Gammasonden zur Sentinel-Lymphonodektomie.

Nuklearmediziner; v. 22(4); Oct 1999; p. 271-280

DisplayCorrelation between accoustic tone and measurement signal

Different measurement conditions

Melanoma Mamma

carcinoma

Prostate

carcinoma

Parathyroid

Sensitivity (+) + + +

Melanoma:

Mostly large distance between SLN and injection spot, good uptake in the SLNs

Mamma carcinoma:

short distance between SLN and injection spot, poor uptake in the SLNs

Sensitivity (+) + + +

Spatial

selectivity

+ + +

Spatial

resolution

+ (head,

neck,etc.)

+

Shielding + + +

Energy

discrimination

+ + +

Wengenmair, H. et al. Qualitätskriterien und Vergleich von Gammasonden zur Sentinel-Lymphonodektomie.

Nuklearmediziner; v. 22(4); Oct 1999; p. 271-280

Minimal requirements for an

intraoperative probe system

Criterion Minimal requirements

Spatial selectivity FWHM ≤ 40°

Spatial resolution FWHM ≤ 15 mm

Sensitivity >> 5cps/kBqSensitivity >> 5cps/kBq

Shielding ≤ 0.1 % of maximum system

sensitivity

Energy selection energy selection possible

Display Acoustic, digital/analoue

Wengenmair, H.. Et al. Qualitätskriterien und Vergleich von Gammasonden zur Sentinel-

Lymphonodektomie. Nuklearmediziner; v. 22(4); Oct 1999; p. 271-280

• Intraopeartive gamma probes and

additionaly „blue-dye“ technique results in

an overall sensitiviyt of more that 90% and a

false negative rate of 8.4%*.

• Possible improvement by Small-field-of-view

gamma cameragamma camera

Newman LA: Current issues in the surgical management of breast cancer.

Abstract. 2002 Breast Cancer Symposium from Heller S. and Zanzonico P.:

Nuclear Probes and Intraoperative Gamma Cameras. Sem. Nucl. Med. 2011

Comparison of preoperative images with intraoperative images Lenka Vermeeren1 et al.: A Portable g-Camera for Intraoperative Detection of Sentinel Nodes in the Head and

Neck Region. J Nucl Med 2010; 51:700–703

In patient with melanoma cranial to left ear, lateral planar lymphoscintigraphy after 2 h (A) showed 2 hot spots caudal to

injection area and weak preauricular hot spot. All 3 hot spots had already been visualized on dynamic scans and on static

planar images after 15 min.

On 2-dimensional and 3-dimensional (B) SPECT/CT fusion, 2 sentinel nodes were localized just ventral to

sternocleidomastoid muscle and 1 preauricular sentinel node was localized within upper part of parotid gland. In

concordance with SPECT/CT, intraoperative images before incision showed injection area and 3 sentinel nodes in same

relation to each other (C).

After excision of first sentinel node, portable g-camera showed remaining sentinel nodes (D),

which were then localized and removed.

Why a portable gamma camera might

be useful?

D. Koppelmann et al.: A newly developed intra-operative gamma

camera: performance characteristics in a laboratory phantom

study Eur J Nucl Med Mol Imaging (2005) 32:1217–1224

Small Field of View Gamma Camera

Intramedical imaging

www.gem-imaging.com

http://crystal-photonics.com/

Kerrou K. etal: The usefulness of a preoperative compact imager, a hand-held

gamma-camera for breast cancer sentinel node biopsy: final results of a

prospective double-blind, clinical study. J Nucl Med. 2011 Sep;52(9):1346-53

M. Tsuchimochi, K. Hayama: Intraoperative gamma cameras for radioguided surgery:

technical characteristics, performance parameters, and clinical applications.

Phys. Medica (2013) 29, 126-138

Detector: NaI, CZT, YAP, CdTe, CsI, etc.

Matrix size: 16x16 – 256 x 256

FOV: 14x14 – 50 x 50 mm

Weight: 700 g – 2200 kg

Handheld-gamma cameraCrystalCam von CrystalPhotonics, Berlin

„Read-out“-elektronics

Cooling system

Front-End Electronics

Pixellierte Anode

CZT-crystal

Cathode

Standard energy range of the gamma camera is 40 – 250 keV.

Acceptance test handheld gamma camera:

Intrinisic measurements

Intrinisic uniformity

Intrinisic energy resolution

Intrinisic uniformity

Integral uniformity 3.2%

Differential uniformity

1.8%

Average: 5.2%

System uniformity

int [%] diff[%]

LEHR 5.8 3.8

MEGP 5.3 3.5

LEHS 5.3 3.0

Acceptance test handheld gamma camera:

System resolution without scatter

Collimator type Distance 0 cm

FWHM [mm] FWTM [mm]

x-direction

y-direction

x-direction

y-direction

LEHR 1.93 2.03 3.49 3.66

MEGP 1.91 1.89 3.46 3.42

LEHS 2.27 2.98 5.17 7.74

System resolution without scatter: 0 mm distance, various collimators

Acceptance test handheld gamma camera:

System resolution without scatter for various distances

Distance from the detector

FWHM [mm] FWTM [mm]

x-direction

y-direction

x-direction

y-direction

0.0 cm 1.93 2.03 3.50 3.660.0 cm 1.93 2.03 3.50 3.66

2.5 cm 3.74 3.89 6.88 8.07

5.0 cm 5.02 4.78 9.00 10.60

System resolution without scatter: various distances, LEHR collimator

Data from Literature: 1.5-18mm*

* M. Tsuchimochi, K. Hayama: Intraoperative gamma cameras for radioguided surgery:

technical characteristics, performance parameters, and clinical applications.

Phys. Medica (2013) 29, 126-138

Acceptance test handheld gamma camera:

System planar sensitivity

The sensitivity measurements were done with 75 MBq99mTc that were filled in a bottle. The analysis of the acquired data was done with a software tool provided by the acquisition software

Collimator type cps/MBq

LEHR 237

MEGP 177

LEHS 554

System planar sensitivity measured for various collimators

Data from Literature: 6.6 – 1600 cps/MBq*

* M. Tsuchimochi, K. Hayama: Intraoperative gamma cameras for radioguided surgery:

technical characteristics, performance parameters, and clinical applications.

Phys. Medica (2013) 29, 126-138

Patient studies

The sentinel lymph node (SLN) is defined as the first lymph node that drains the primary tumor basin. The SLN can be mapped by using a sulphur-colloid radiotracer labeled with 99mTc that is injected labeled with 99mTc that is injected near the primary tumour. Approximately 18- 37 MBq of tracer is injected near the primary tumor, with up 74 kBq of activity accumulating in the sentinel lymph nodes after it drains through the lymphatic channel. Till now 27 patients were imaged using the novel handheld gamma camera system.

Pat, 70y, f, N. Mammae, left,

Injection of 22 MBq 99m Tc Sentiscint

Millenium VG, GE Healthcare

Handheld, CrystalCam

Patient, 45Y, penis carcinoma

SPECT Image fusion

Handheld

Infinia, GE Healthcare

Handheld gamma camera setup

3 h 24 h 48 h

Ga67-DOTA+ Nanoparticle + PTR

48h

SurgicEye

The declipse®SPECT Ultrasound Fusion consists of

a high precise optical navigaton system,

a gamma detector

a high resolution ultrasound system.

SurgicEye GmbH, Munich, Germany

Thank you very much for your audience